For people who choose not to be tracked, Google developed a plug-in that persists even after cookies are cleared. Most other systems for opt-out rely on cookies. Given that most people who are concerned about their privacy clear their cookies periodically, it was important to EFF that Google’s opt-out mechanism would remain even if all cookies were cleared.

Even more interesting was Google’s decision to link a page to the caption “Ads by Google” that explains the behavioral targeting technique with a list of interest categories that have been assigned to you. In other words, Google is making more transparent what they know, or think they know about you. You can then choose to remove some of those interest categories or to opt-out of tracking altogether.

As Zimmer points out, Google could show more fine-grained detail regarding what they know about you. But it’s still a fascinating step for a major corporation to take. Even better, Google isn’t the only one creating pages that show users how they’re being viewed for marketing purposes.

BlueKai and eXelate Media run “behavioral exchanges,” selling information to companies about website visitors. Like Google, they both provide pages, here and here, where people can choose to opt-out of tracking altogether. Otherwise, they can monitor and edit what interests are associated with them.

It’s hard to know how “transparent” all this really is to people who are not tech and privacy geeks. Ultimately, companies need to improve data collection practices for everyone, not just people who care enough to find out. And I would argue that it can’t be a model where a select few can just opt-out and protect themselves, and the companies can continue to do anything they want to do with everyone else’s data. But it’s still a new way of managing your life online that doesn’t require as much investment in self-education and time as the many of the other methods described by EFF in its Surveillance Self-Defense Site.

Will this model become the dominant one in online tracking? Compare the transparency of these companies with RealAge, an online quiz that’s just been outed as selling information to pharmaceutical companies who want to market directly to quiz takers. What most consumers find instinctively distasteful is a feeling of being fooled. RealAge claimed that it protected privacy by not giving personally identifiable information to the companies and that it is “providing value in return for the information” with ads that might interest the quiz takers, but it’s not the kind of value RealAge users consciously “paid” for. What BlueKai, eXelate Media, and Google have shown is an understanding that for many people, their privacy is violated not just when a company knows such-and-such information is associated with Mr. Tom Smith, but when any of that information is being collected and shared without the full knowledge and consent of Tom Smith.

It’s obvious why RealAge chose to be vague about where their profits came from–would 27 million people have taken the test if the website had declared prominently that the information would be sold to pharmaceutical companies? But it’s hard to see how sustainable that business model is. Presumably, BlueKai and eXelate Media, as well as Google, will also get somewhat less data with their more transparent strategy. But what model of business will still be around ten, twenty, fifty years in the future?